In addition to being the site of the comemoration of the signing of the Magna Carta, Runnymede is home to the memorial to JFK:

The British memorial to the assassinated President Kennedy was jointly dedicated in May 1965, by Queen Elizabeth II and Jacqueline Kennedy, prior to a reception for the Kennedy family at Windsor Castle. The memorial consists of a garden and Portland stone memorial tablet inscribed with the famous quote from his Inaugural Address:
“Let every Nation know, whether it wishes us well or ill, that we shall pay any price, bear any burden, meet any hardship, support any friend or oppose any foe, in order to assure the survival and success of liberty.”
Visitors reach the memorial by treading a steep path of irregular granite steps, intended to symbolise a pilgrimage. There are 50 steps in total. Each step is different from all others, with the entire flight made from 60,000 hand-cut granite setts. Landscape architect Geoffrey Jellicoe designed the garden; sculptor Alan Collins designed and carved the stone inscription. The area of ground on which the memorial is situated was given as a gift to the United States of America by the people of Britain. (Though property ownership was transferred to the federal government of the United States, the area remains under the sovereignty of the United Kingdom) It is maintained by the Kennedy Memorial Trust, which also sponsors educational scholarships for British students to attend university in the United States. – Wikipedia~